At present, since the diffusion rate of electric cars is lower than the diffusion rate of gasoline-powered cars, it rarely happens that charge stations (CS: Charge Station), which are facilities for charging electric cars, are crowded.
However, in the future, if electric cars will gain in popularity, the congestion at charge stations will pose a serious problem, like traffic congestion.
Thus, in order to avoid congestion occurring when electric cars come to some charge stations, it is necessary to inform drivers of charge recommendation information which indicates which charge station can provide smooth charging, thereby leveling the congestion at charge stations.
As a technique for informing drivers of charge recommendation information, for example, there is known a technique wherein the current positions and residual battery capacities of all electric cars are measured, and then charge recommendation information is generated based on the measured results, and the drivers are informed of the generated charge recommendation information.
However, in the above-described technique, it is necessary to measure the current positions and residual battery capacities of all electric cars running, for example, on a toll road or the like, and there is such a problem that this is difficult to realize at present.